Artificial knee is built for extreme athletes

Several competitors in ESPN's Summer X Games will be wearing a prosthetic knee made by Biodapt in Minnesota designed to meet the demands of such sporting events as mountain biking and motocross races. The Moto Knee features mountain-bike-style shock absorbers and can be flexed to as much as 135 degrees, compared with 90 degrees for other artificial legs. The company has sold about 75 of the prostheses to athletes and veterans.